The proposed program will investigate nuromuscular mechanisms underlying speech and non-speech motor control of the lips and the jaw. Studies will be conducted on normal speakers, speakers with neuromuscular impairments, normal non-human primates, and non-human primates with induced neurological damage. The techniques employed will vary from EMG and movement recording, in human subjects, to central nervous single unit recording in non-human primates. The initial phase of the program will include four major studies: analysis of lip and jaw movement parameters in normal and abnormal speakers; measurement of lip and jaw muscle forces and mechnical properties; analysis of normal and abnormal reflexes in facial and mandibular muscles; and representation of bulbar-suprabulbar interactions in normal and damaged neurological systems. The quantitative methods of engineering control theory will be applied as a means of synthesizng these various data into a working mathematical representation of the speech motor control system. An on- line hybrid computer facility, especially designed for speech physiology research, will be employed to assist in control system simulation of speech motor functions.